Electroplating of Fe-Rich NiFe Alloys in Sub-50 nm Lines

The performance of 2-Mercapto-5-benzimidazolesulfonic acid (MBIS) in a Watts bath in crack electro-healing was investigated. Potentiostatic and galvanostatic voltammetry, current efficiency measurements were performed for electrochemical investigation. The morphology of the healed crack indicates that the healing crystals grow in a controllable manner with the addition of MBIS under forced convection with the healing crystals fill preferentially in the crack tip to the crack sidewalls. No obvious defects were observed along the interface between the substrate and the healing crystals, which is attributed the much higher current efficiency of MBIS. Annual-ring like defects are observed but with a much longer width compared with PEI. The formation mechanism of annual ring is discussed. Possible approach to get defect-free crack healing is also prospected.

Section: Resultsmentioning

confidence: 99%

Evaluating the Performance of 2-Mercapto-5-Benzimidazolesulfonic Acid in Controllable Electro-Healing Cracks in Nickel

Zheng

Shi

2015

“…3,4,[18][19][20][21][22] Although Ni-Fe alloys can be prepared using various techniques such as sputtering and ball milling, electrodeposition may be the most feasible for low-cost mass production. The electrodeposition of Ni-Fe alloys from aqueous baths, therefore, have been widely studied, 3,4,[18][19][20][21][22] 20 can be easily prepared using electrodeposition. The electroplating baths of Ni-Fe alloys are composed of simple salts with or without complexing agents.…”

mentioning

confidence: 99%

Voltammetric Study and Electrodeposition of Ni(II)/Fe(II) in the Ionic Liquid 1-Butyl-1-Methylpyrrolidinium Dicyanamide

Chung

Chuang

et al. 2015

Ionic liquid 1-butyl-1-methylpyrrolidinium dicyanamide (IL BMP-DCA) was used as the electrolyte to study the voltammetric behavior of Ni(II) and Fe(II) introduced into the IL as their chloride and sulfate salts. Compared with the aqueous system, the separation of reductive potential between the Ni(II) and Fe(II) was significantly decreased in this IL. The electrodeposition of Ni-Fe alloys was thus easily achieved using constant-potential electrolysis at copper substrate. No anomalous electrodeposition of Ni-Fe, which is common in aqueous system, was observed in this IL, resulting in the easy control of alloy compositions. The electronic spectra indicated that the coordinations of Ni(II) related to the precursors used in the IL, and the surface morphology of the Ni-Fe alloys was affected by the precursors as well as the electrodepositing potentials. Crystalline Ni and Ni-Fe were obtained from this system but crystalline Fe was only obtained at high temperature. The obtained Ni-Fe alloys were converted to the corresponding metal oxides/hydroxides via electrochemical oxidation in alkaline solution, and the linear scan voltammetric study indicated that these Ni-Fe alloys are potential substitutes for Pt as electrocatalysts of oxygen evolution reaction. Ni-Fe alloys are important materials that have been investigated for multiple applications including magnetic materials, 1-4 electrochemical multivalent memory, 5 and highly active electrocatalysts of oxygen evolution reaction (OER). [6][7][8][9][10][11][12][13][14][15] Recently, Ni-Fe alloys have attracted much attention because OER is crucial to energy storage/conversion such as rechargeable metal-air batteries and electrochemical watersplitting. For the latter one, the potentials of both electrodes always determine the cell voltage. The OER is usually the rate determining step and contributes more significantly to the amount of potential required beyond the theoretical cell voltage. The cell voltage can be efficiently decreased by using an efficient electrocatalyst as the anode to reduce the overvoltage of OER, but precious metal-containing electrocatalysts should be avoided because of their high cost. Ni-Fe alloys, therefore, show their advantages to be OER electrocatalysts. Ni-Fe alloys are also used for hydrogen evolution reaction (HER) 16 and for the electrodetection of an important organic molecule, 4-aminophenol. 17 Electrodeposition is widely utilized to prepare metal alloys, including Ni-Fe alloys. 3,4,[18][19][20][21][22] Although Ni-Fe alloys can be prepared using various techniques such as sputtering and ball milling, electrodeposition may be the most feasible for low-cost mass production. The electrodeposition of Ni-Fe alloys from aqueous baths, therefore, have been widely studied, 3,4,[18][19][20][21][22] 20 can be easily prepared using electrodeposition. The electroplating baths of Ni-Fe alloys are composed of simple salts with or without complexing agents. The complexing agent-containing baths are more stable, especially at high pH.28-30 However...

“…3,5,7 To address these copper damascene extendibility issues, alternative metals, such as cobalt, are being actively explored for use in interconnects. [7][8][9][10][11][12][13][14][15][16][17][18] In terms of bulk resistivity, copper is significantly superior to cobalt. However, cobalt has a much shorter mean free path than copper, so it is expected to have superior scalability of resistivity to smaller line dimensions due to reduced scattering at material interfaces and grain boundaries.…”

mentioning

confidence: 99%

The Critical Role of pH Gradient Formation in Driving Superconformal Cobalt Deposition

Rigsby

Brogan

Doubina

et al. 2018

Conventional damascene electroplating uses a combination of organic additives, namely, a suppressor, an accelerator, and a leveler, to achieve superconformal fill of interconnects. This work demonstrates an alternative mechanism that produces bottom-up cobalt deposition through a combination of pH and suppressor gradient formation within the patterned features. The fill mechanism was investigated using voltammetric and electrochemical quartz crystal microbalance measurements. The results show that local pH affects both the deposition rate and the current efficiency for cobalt deposition, which, combined with the kinetic effects of suppressor-type additives, drive a plating rate differential between the field and the feature-bottom. By appropriately selecting solution concentrations, organic additives, the waveform, and the mass transport conditions, void-free superconformal cobalt fill can be achieved in a variety of features.